Write an equation to describe the sequence below. Use n to represent the position of a term in the sequence, where n=1 for the first term. –1,4,–16,…Write your answer using decimals and integers.an=____(____)n−1
Q. Write an equation to describe the sequence below. Use n to represent the position of a term in the sequence, where n=1 for the first term. –1,4,–16,…Write your answer using decimals and integers.an=____(____)n−1
Identify Pattern: Identify the pattern in the sequence.The given sequence is −1,4,−16,…We notice that each term changes sign and is multiplied by a common ratio.This indicates that the sequence is geometric with alternating signs.
Determine Terms: Determine the first term a1 and the common ratio r. The first term is a1=−1. To find the common ratio, we divide the second term by the first term: r=(−1)4=−4.
Write Formula: Write the general formula for the nth term of a geometric sequence.The nth term of a geometric sequence is given by an=a1⋅r(n−1).
Substitute Values: Substitute the values of a1 and r into the formula.We have a1=−1 and r=−4.So, the formula for the nth term is an=(−1)×(−4)(n−1).
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